Characterization of Purified Polygalacturonase Produced by The Local Isolate (B36) of Bacillus megaterium

Abstract

Characterization of the purified polygalacturonase which was produced by the local isolate (B36) of Bacillus megaterium was studied. The isolate was gave maximum enzymatic activity by using submerged cultures. The molecular weight of the enzyme was 65kdalton by using SDS-PAGE, the optimal pH of the enzyme activity was 7.0, and the enzyme activity was 1639.256 unit/ml, the optimal temperature of the enzyme activity was 50C, and the activity was 1619.673 unit/ml. The pH of polygalacturonase stability was between (6.5-7.5) but the thermo stability of the enzyme was between (0-50)ºC. The effect of some ions, chelating compounds and reducing agents onenzyme stability was also studied, Mn+2, Fe+3 and Ca+2 were increased the enzymatic activity to 115%, 105% and 110% respectively at the concentration 5mM, but Cu+2 inhibited the enzymatic activity to 10% at 1mM and the inhibition was increased to 50% at 5mM, while Mg+2 increased the enzymatic activity to 110% at 1mM, and 130% at 5mM. The urea and EDTA did not effect on activity at 1mM but inhibited the activity to 30% and 60% respectively at 5mM, also SDS inhibited the activity at 0.1%(wt/v). The kinetics constants of the enzyme were 3.125%for Km and 0.043 unit/ml for Vmax.The activation energy for the enzymatic reaction was 38.613 kcal/mole.